Exchange-biased nanoscale materials with multiple interfaces prepared by ion implantation.

Exchange bias, which results from the interaction between a ferromagnet and an antiferromagnet, is typically manifested by a shift and broadening of the hysteresis loop. It has gained technological importance since it is used to establish a reference direction in spintronic devices. The bulk of exchange bias research has been focused on thin films in which Co and CoO are the archetypal ferromagnetic and antiferromagnetic materials, respectively. Essentially, the formation of CoO relies on the use of natural surface oxidation, which is a self-limiting process, resulting in an oxide thickness of a few nanometer. Recently, in order to overcome this limited thickness of the antiferromagnet, ion implantation has been demonstrated to be suitable to form CoO embedded in a thin Co film. However, little is known about the structure of the antiferromagnetic constituents and the depth dependence of the exchange bias properties. It is the aim of this work to gain insight into the structural and magnetic aspects of O-implanted ferromagnetic systems (Co, Fe and Ni) along depth and to study the effect of physical confinement on exchange bias in ferromagnetic/antiferromagnetic nanostructures prepared by lithography and ion implantation.

Keywords:Exchange Bias, Patterning, Ion implantation, Magnetic nanostructures, Magnetic thin films

Disciplines:Nuclear physics